Air compressing mechanism



Sept. 7, 1937. I JQDRY 2,092,717

AIR COMPRESSING MECHANISM Filed April 1, 1935 7 Sheets-Sheet i 1937. E. J. JODRY 7. 2,092,717

V AIR COMPRESSING MECHANISM I Filed April 1, less I 7 Sheet-Sheet :s

Sept. 7, 1937.

E. J. ,JQD Y AIR COMPRESSING MECHANI SM Filed April 1, 1935 7 Sheets-Sheet s gii Hiiii" 16 82 Sept. 7, 1937.

E. J. JODRY AIR COMPRESSING MECHANISM 7 Sheets-Sheet 7 Filed April 1, 1935 Patented Sept. 7, 1937 PATENT OFFICE AIR COMPRESSING MECHANISM Edward J. Jodry, Tamaqua, Pa., assignor of forty-five per cent to Henry J. Lenhardt,

Hazleton, Pa.

Application April 1, 1935, Serial No. 14,175

22 Claims.

The present invention relates to air compressing mechanism.

More specifically, the invention relates to air compressing mechanism in which hydraulic pressure is utilized for actuating a pair of interconnected master pistons reciprocably mounted within master cylinders, the hydraulic fluid preferably being oil which is forced into the master cylinders through a control valve which functions to admit the oil to the cylinders in such manner that the pistons are given their air compressing movement alternately, the oil being delivered to the valve by means of a suitable pump. The mechanism also includes a relief valve for successively relieving the pistons of fluid pressure in their non-compressing movement. The cylinders are provided with'intake valves for admitting atmospheric air to the cylinders during the ineffective movement of the pistons and exhaust valves for exhausting the air compressed by the pistons, a suitable storage tank being provided which is connected by means of a suitable tube or duct with the exhaust valves. A primary object of the present invention is to provide an air compressing mechanism of the character stated in which a pair of master pistons are hydraulically operated within a pair of mastcr cylinders for compressing relatively large volumes of air therein, and in which the master pistons are interconnected in such manner that provision is made for actuating a plurality of secondary pistons within secondary cylinders said pistons are disposed. is automatically controlled.

A still further object of my invention is the pro on of a pair of relatively large cylinders, a relatively small cylinder coaxial with each of said large cylinders, a movable cylinder telescopically engaged with each of said small cylinders and movable within the large cylinder, and

pistons carried by each of the movable cylinders and cooperating with the large and small cyl- 55 inder for alternately compressing air therein upon movement of the movable cylinder in opposite directions.

A still further object of my invention is the provision of a pair of cylinders, a compressing piston within each of said cylinders, a fluid pump for providing fluid pressure for actuating the pistons, and valve means automatically operable by the movement of the pistons for controlling the fluid from the pump in such manner that the pistons will be pressure actuated alternately.

A still further object of my invention is the provision of air compressing meansincluding a pair of cylinders in which are disposed primary compressing pistonsQa second pair of cylinders within which are disposed secondary compressing pistons which are operated directly by the primary pistons, a multiplicity of other cylinders Within each of whichis an air compressing piston and all of which are operatively connected with the primary pistons for actuation thereby together with means for supplying fluid pressure successively against the primarypistons, and valve means automatically controlled by the primary pistons for controlling the flow of oil to and from the cylinders within which the primary pistons are disposed.

A still further object of my invention is the provision of air compressing mechanism of durable construction and which is highly eiiicient in operation.

With the foregoing objects in view'as well as others-which will'become apparent from the fol-' Fig. 2 is a top planview of the structureillus-- trated in Fig. 1.

Fig. 3 is a vertical sectional view on an enlarged scale through the compressing cylinders and certain associated parts.

Fig. 4 is a vertical sectionalview of the reversing valve, the section being taken substantially on the line 44 of Fig. 5.

Fig. 5 is a vertical section on the line 5--5 of Fig. 4.

Fig. 6 is a horizontal section on the line 6-6 of Fig. 4.

Fig. '7 is a vertical sectional view of a fluid pump as .seen on the line 'l-'| of Fig. 8.

Fig. 8 is a sideelevational view of the pump.

Fig. 9 is an end elevational view of a relief valve.

Fig. 10 is a vertical sectional view substantially on the line IUI0 of Fig. 9.

Fig. 11 is a, fragmental vertical sectional view through intake and exhaust valves as seen on the line HH of Fig. 12.

Fig. 12 is a top plan view of the structure illustrated in Fig. 11.

Fig. 13 is a top plan View of the exhaust valve seat.

Fig. 14 is a side elevational view of a modified arrangement of compressing cylinders.

Fig. 15 is a top plan view of the structure illustrated in Fig. 14.

Fig. 16 is a side elevational view, partly in section disclosing cylinder arrangements which may be operatively associated with the main piston actuating means.

Fig. 17 is a vertical sectional view of a modified form of piston.

Referring to these drawings for a detailed description of my invention and in which like reference characters designate like parts, C designates an air compressing unit which in its preferred form comprises a pair of cylinders l8 which are supported on a supporting member II and secured thereto by means of ring members l2 threadedly engaged with the cylinders and flanged ring members i3 on the opposite side of support H and held in engagement therewith by means of bolts l4 threaded into ring members Each of the cylinders I0 is provided with a top cover plate l5 which is secured to the cylinder by means of a ring 'member l6 threadedly engaged with the cylinder and detachably connected with the cover plate by means of bolts l1. The cover plate I5 is provided with three threaded apertures l8 two of which receive an externally threaded valve seat I9, only one of which is illustrated in section in Fig. 1.1. The other aperture [8 receives an externally threaded valve seat 2|. Cooperating with each of the valve seats [9 is an intake valve .22 which is held in engage ment with its seat l9 by means of a spring 23 surrounding a valve stem 24 and held under compression between the valve seat and a washer 25 backed by a nut 26 and a lock nut 21. Cooperating with the valve seat 2| is an exhaust valve 28 which is slidably mounted on a valve stem 29 and yieldably maintained in engagement with the seat 2| by means of a spring 3%] held under compression between the valve 2| and a washer 3| backed by a nut 32 and a lock nut 33. The valve seats are each in the form of a disk having a plurality of air apertures I 911. and 21a with a bevelled seat surrounding the apertures as is more particularly indicated in Fig. 13.

By the provision of the arrangement just described each of the cylinders I0 is provided with an exhaust valve and a pair of inlet valves which function to discharge compressed air from and to admit air under atmospheric pressure and air above atmospheric pressure in a manner to be hereinafter described.

Each of the valves 22 and 28 is preferably enclosed in a suitable housing which facilitates at tachment of duets with valve 28 and one of the valves 22 and each of the housings preferably comprises a cylinder 35 suitably secured to the cover plate l5 and a cover 36, two of which are provided with a threaded aperture 31, the aperture in the other cover 36 may have a suitable screen applied thereto for straining the air admitted thereto thus precluding any possibility of dirt lodging under the valve. Suitable gaskets 38 and 39 are preferably disposed between the cylinder 35 and the covers l5 and 36 respectively.

Associated with each of the cylinders I0 is a smaller cylinder 4| the upper end of which projects through the support II and the lower end of which is threadedly engaged with a flanged ring member 42 which is secured by means of bolts 43 to a suitable base 44. The base 44 is provided with a pair of threaded apertures 45 opening into each of the cylinders 4| and threadedly engaged within the apertures 45 are valve seats 45 and 4'! for intake and exhaust valves 48 and 49 respectively which valves are yieldably held in engagement with their seats by means of springs 5| and 52 respectively. Surrounding the valves and their associated springs are suitable housings each comprising a cylinder 53 and a cap 54 threadedly engaged therewith, suitable gaskets 55 and 56 being disposed between the cylinders 53 and base 44 and caps 54 respectively. The cap associated with the exhaust valve is provided with a threaded aperture 5! while the cap associated with the intake valve is provided with a non-threaded aperture 58.

Disposed for vertical reciprocation within each of the cylinders l0 and exteriorly of the respective cylinder All is a cylinder 6?! the upper end of which is provided with a suitable piston P which in a preferred form comprises a circular plate 6! which is secured to the cylinder by means of screw bolts 62 threadedly engaging a ring member 63 in turn having threaded engagement with the cylinder. The plate BI is provided with a piston ring 4 and the ring member G3 is provided with a piston ring 65 which yieldably engages a uexible member 65 for mainta ning same in fluid sealing engagement with the wall of cylinder iii, the flexible member 66 may be of leather or any other suitable material and is held in position between plate El and ring member 63 as is clearly illustrated in Fig, 3. It is to be understood however that member 66 in some instances may be omitted and ring 63 caused to directly engage the cylinder wall.

Each of the cylinders 60 as before stated is adapted for vertical reciprocation through the support I I and for reasons hereinafter to appear it is necessary that a fluid tight engagement be provided for the cylinder adjacent the support I I. Accordingly, a packing gland is provided and which comprises a bronze ring 68, a second bronze ring 69 and suitable packing 10 disposed between the rings 68 and 69, the ring 69 being held in compressive engagement with the packing by means of a flanged ring member H which threadedly engages the ring member I3 as is clearly indicated in Fig. 3.

Disposed for vertical reciprocation within each of the cylinders 4i is a suitable piston 72 and which preferably comprises circular plates '1'? and 3 each provided with a piston ring M, the piston ring of plate 73 maintaining a flexible member '15 in fluid sealing engagement with the Wall. of cylinder 4i. The flexible member 15 in this piston may also be omitted in which instance both rings M will engage the cylinder wall.

The piston P is movable with the piston p and accordingly a rigid connection is provided between the pistons and which preferably comprises a rod '56 havin screw threaded engagement with piate SI and plates 32 and '63, the screw threaded engagement with plates 72 and 73 serving to maintain the flexible member 75 in fixed engagement between the plates I2 and I3. This threaded engagement of rod I6 with plates I2 and I3 further provides for adjustment of piston 10 relative to the piston P.

The ring members I2 are provided with oil intake. ports I? and I8 and oil exhaust ports I9 and respectively for connection with fluid ducts and in order that fluid may be admitted within each cylinder I0 and under the piston P when in its lowest position such ring members are preferably bevelled as indicated at 8| in Fig. 3. This arrangement however is not absolutely necessary as the ring members may be modified in such manner as to have the ports disposed vertically of the planes of the ring members and communicate with channels formed in the bottoms of the ring members which in turn communicate with the interior of cylinders I0.

The arrangement of cylinders and pistons just described provides a pair of major compressing chambers 0 within cylinders I0 and a pair of minor or secondary compressing chambers (2 within cylinders II. A pair of piston operating fluid chambers e are also provided within cylinders I0 and exteriorly of cylinder 60.

Secured to the lower end of each of the cylinders 60 by threaded engagement therewith is a ring member 82 to which is secured by means of bolts 83 a bronze guide plate 84 which upon reciprocation of cylinder 60 engages cylinder 4| to maintain cylinder 60 in proper alignment as well as to prevent escape of air from chamber d. Each of the ring members 82 is provided with a pair of diametrically disposed studs to each of which is pivotally connected one end of link 86, the opposite end of which is pivotally connected to a stud 81 carried by the corresponding end of a walking beam or lever 88 each of which beams is pivotally connected at 89 through a suitable bushing to a bracket member connected by bolts 9I to the support II. Each of the walking beams 90 is provided with a pair of apertures 92 and 93 for a purpose hereinafter described.

By the provision of the walking beam connection between the lower ends of cylinders 60, pistons P are positively operated synchronously in opposite directions and furthermore such walking beams provide a convenient arrangement for actuation of fluid control valves in a manner hereinafter described.

My invention also comprises a fluid pump PI for forcing fluid into the chambers e for actuating the pistons P. The pump as is more particularly illustrated in Figs. '7 and 8 comprises a casing I00 the base of which is provided with apertures I0! for the reception of bolts or other securing means for securing the casing in fixed position. The casing I00 is provided with three chambers I02, I03, and. "Min which are disposed centrally thereof shafts I05, I06, and I01 respectively to which shafts are suitably secured gears I08, I09, and H0 respectively. The shaft I06 to which is secured the gear I09 is extended beyond the casing I00 and. is suitably connected with a motor M which is illustrated in Fig. l as an electric motor but which may be a gasoline motor or any other suitable source of power.

Disposed within casing I00 are ports whose axes are substantially tangential to the gears at their tooth engaging portions and which ports comprise a pair of inlet ports H2 and I I3 and a pair of exhaust ports II 4 and H5 which ports are in communication with fluid conveying ducts or tubes as hereinafter described.

Operatively associated with the compressing unit C and pump PI is a reversing valve V which is more particularly illustrated in Figs. 4, 5, and 6 and which comprises suitably cored castings I I1 and H8 having plane engaging surfaces which are maintained in contact by bolts I I9 engaged in cooperating lugs I2I and I22 carried by the castings Ill and I I8 respectively. A suitable gasket is preferably disposed between the castings II! and H8. The casting II I is provided with a cylindrical opening I24 extending throughout the length thereof and the opposite ends of the opening are closed by detachable cover plates I25 secured to the casting by bolts I26, suitable gaskets preferably being disposed between the casting III and the plates I25. The casting II! is also cored out around, below, and to the side of the opening I24 for providing a fluid pressure chamber I28. The casting I I1 is further provided with a pair of ports I29 and I30 which are in communication with opening I24 adjacent the opposite ends thereof and through the base of the casting.

The casting II8 is suitably cored to provide ports I3I and I32 which open through the sides of the casting as well as through the face thereof which engages casting In for communication with the chamber I28. The casting H8 is also provided with apair of ports I33 and I34 which open from opposite ends of the casting and through the surface thereof which engages casting Ill. The casting H8 is further provided with a port I35 which is in communication with port I3! and the face of the casting which engages casting I I I. The casting I I8 is further provided with a pair of ports I36 and I3? which open through the face thereof at points aligned with port I35 and ports I29 and I30 in casting I IT.

The ports I3I, I33, and I34 are controlled by a slide valve I40 which as indicated more clearly in Figs. 4 and 5 is in the form of a casting having a semicylindrical recess I4I of sufficient length to interconnect port I3I with port I33 or with port I34 and is also provided with an extension I42 which is received within a recess I43 of a cylindrical valve actuating'plunger I44 which is reciprocally mounted within opening I 24 and is maintained against rotation about its axis by means of the inner end of a bolt I45 threaded into casting I I! and engaging within a recess I46 in the plunger I44. The valve I40 is further provided with laterally disposed extensions I4'I which are disposed at opposite ends of the ports I3I, I33, and I34 and which function to preclude any interference between the edges of the ports and the valve upon reciprocation thereof.

The plunger I44 is recessed out at opposite ends thereof as indicated at MM. and communicating with such recesses are rectangular recesses I42 for alternate communication with ports I29 and I30.

Ports I35, I36, and I3'I are controlled by a valve I49 which is'substantially in the form of valve I 40 and is adapted to place port l35 into communication with. port I36 or port I 31. The valve I49 is provided with a vertically disposed channel I50 within which extends an arm I5I of a lever I52 which is connected with a shaft I53 which in turn is provided with an actuating arm I54 having an aperture I 55 in the free end thereof.

Since it is important that the fluid chamber I28 be positively sealed against oil leakage the shaft I53 is preferably extended through a packing gland I56 which is maintained in sealing engagement with the shaft by means of a cup shaped nut N51.

The compressing unit C has operatively associated therewith a relief valve R illustrated in detail in Figs. 9 and 10 and which comprises a casing 565! provided with a frusto-conical bore IGI in which is disposed a rotatable valve member Hit of the same configuration as that of the bore. The casing I6!) is provided with ports I63, I64, and 55 and the valve I62 is provided with an L-shaped port I66 for placing port I63 selectively into communication with port I64 or port I 55. The casing IE is provided with suitable at-- taching feet Ifil and the opposite ends of easing H30 are threaded for engagement therewith of cap members I68 and I69, the cap member I68 enclosing a spring I'II which urges the valve I62 into fluid sealing engagement with casing I60. The cap I69 encloses a packing gland I12 through which extends the operating spindle I'I3 to which is secured an actuating arm I14 provided with an aperture H in the free end thereof for connections hereinafter described.

The construction also includes a fluid reserve tank T which is provided with a T-shaped connection ill for attachment of certain ducts or tubes later described. In practice a suitable air bleed valve will preferably be disposed in the connection ill for escape of air which may become entrapped in the oil.

The construction also includes a compressed air storage tank S which may be of suitable construction and of any desired capacity and which is preferably provided with an inlet valve I18, an outlet valve H9 and a drain valve IN. The tank is also preferably provided with a suitable gauge I82 and a relief valve I83.

The different operating elements entering into my invention having been described in detail their connection and cooperation with one another will now be described.

In the preceding description various ports were referred to which ports as will now be described are put into communication in a specific relation by means of ducts or tubes which preferably are of copper stock but not necessarily limited thereto and while such ducts or tubes are all illustrated as of the same diameter it is not intended that they shall necessarily be so in actual practice and such tubes may be of greater or lesser diameter proportionately than as illustrated. Furthermore, the tubes are illustrated in a more or less diagrammatical manner and in actual practice they will in all probability be arranged in a much more compact arrangement.

The pump PI whose function is to supply fluid such as a suitable oil to the chamber 6 has connected with its hereinbefore described ports oil ducts which are connected as follows. A tube 5 {it interconnects port II5 of the pump and port 532 in valve V. A tube I9I interconnects port I 52 in the pump and port I3I in valve V. A tube I92 interconnects port II4 in the pump and one branch of connection H1 in tank T. A tube I93 interconnects port H3 in the pump and a tube I94 which is connected with the other branch of connection Ill and also with port I63 in the relief valve R. The other two ports I64 and I65 in the relief valve R, are connected by tubes I95 and I96 to ports and 80 respectively of the ring members 52. The diametrically opposite ports ll and E8 in ring members I2 are connected by means of tubes 5% and I99 with ports I33 and I34 respectively in the valve V.

It will be noted that each ring member I2 is provided with a pair of diametrically disposed ports one of which is an intake and the other of which is an exhaust for the fluid forced by the pump into chamber e, and in order that the air compressing pistons may reciprocate in opposition, that is, when one piston is moving up the other piston is moving down as is indicated in Fig. 3, it is necessary that fluid under pressure be admitted through tubes I98 and I99 alternately to chambers c and that the chambers be relieved alternately, and accordingly operating connections are provided for properly actuating valves V and R and which connections are preferably actuated through the oscillation of one of the walking beams 88.

The valve V which is operated eonjointly by fluid pressure and mechanically has its latter movement effected by means of a rod one end of which is pivotally connected at 202 at the aperture I in arm I5 1 of valve V while the other end of the rod is pivotally connected at 293 to the longer arm of a bell crank lever 264 pivoted at 205 to a bracket 2%. The shorter arm of the bell crank lever is provided with a pin 207 which rides within a slot 288 in a link 2139 which is pivotally connected at 2E9 on a suitable pin secured within aperture 92 in walking beam 88.

The relief valve R is similarly operated and which is effected by means of a lever 2 I2 the end of whose longer arm is provided with a slot 253 in which rides a pin 2 i l suitably secured in aperture H5 in arm lid of the relief valve, the slot being provided to allow movement of the pin as a result of the cooperative angular and rotative movements of lever 2I2 and arm I74. The lever 2I2 is pivoted at 2H3 to bracket H 3 and the shorter end of the lever 2E2 pivoted at 2! l to one end of the link 2H3 whose opposite end is provided with an elongated slot 2E9 in which rides a pin 222i which is suitably secured in aperture 93 in walking beam 88.

While the connections for operating the valves V and R are disclosed as including slotted links it may be found desirable to provide adjustments for controlling the time of actuation of the valve and accordingly the links 269 and ZIS may be replaced by tubular rods provided with suitable adjustable stops on either side of the shorter arm of bell crank lever and the engagement between lever 88 and link 2 I8 in which case the shorter arm of lever 28 as well as the lever 88 would preferably be provided with swiveL ly mounted collars embracing the tubular rod and adapted for alternate engagement with the adjustable stops.

The support I i and base member 43 may be of any desired construction but are preferably of rectangular configuration and due to their supporting function should be maintained in fixed vertically spaced relations which is preferably accomplished by means of suitable spacing rods 223.

In operation of the improved mechanism described the pump P2 is driven by motor M. and which through the intermeshing gears I02, I03, and IM provides a circulation of oil in the following manner. Oil will be drawn from the reserve tank T through tube !33 and also from valve V through tube Hill and will be forced under pressure through tube H30 into chamber I28 in valve V and in which chamber will always be maintained a volume of oil under pressure; and with the parts in the positions illustrated in Figs. 1 and 3 with the left hand cylinder 60 at the limit of its upward stroke and the right hand cylinder to at the limit of its downward stroke, the walking beam 88 will have drawn the link 2E9 upwardly and immediately preceding the final upward movement of the left hand cylinder til the end of slot 288 will have engaged pin 2il'l thereby causing lever fiil l to be swung in a clockwise direction thus moving rod 2ill to the right and which through its connection with arm I56 has moved slide valve M9 to the position indicated in Fig. '6 whereby port I37 has been placed in communication with chamber 828 thus introducing fluid pressure into port E38 and causing piston Hi l to move to the position indicated in Fig. 4. This movement of the piston moves slide valve M leftward or to the position indicated in Fig. 6 whereby port I3 3 is put into communication with chamber I28 resulting in the flow of oil under pressure from port i3 5 through tube I99 and through port it in ring member I2 thereby admitting oil under pressure in chamber e for forcing the piston P upwardly for compressing air in chamber 0.

Simultaneously the port Si! in the same ring member it? or the tube i236 connected therewith must be closed through the relief valve R, which was effected immediately preceding the final downward movement of the right hand piston P I by engagement of pin 22l with the lower end of slot 259 which through the connections heretofore described moved the valve N52 to the position indicated in Figs. 9 and 10.

As the right hand cylinder begins its upward movement the left hand cylinder 69 will begin its downward movement, at which time oil will be drawn from chamber 6 through port 11, tube Hi8, ports B33 and I3l which are in communication through the slide valve I40 and through tube Hi1 to pump Pi and which oil will be discharged through tube I92 to the reserve tank T. At the same time port I9 through tube I95 will be in communication with the reserve tank as well as with the pump PI through the revers- As the right hand piston P approaches the limit of its upward movement by fluid pressure within chamber 6 the links 269 and 2I8 through engagement with pins 2M and 22I with the opposite or upper ends of the slots 2% and 209 will move arms I54 and FM to their opposite positions whereby the slide valve M9 will be moved to the right in Fig. 6 thereby placing port I36 in communication with chamber l28 which will admit fluid pressure into port l2!) resulting in the movement of plunger IM to the right thus placing port I33 in communication with chamber I28. Accordingly, fluid under pressure will be admitted to chamber e under the piston of the left hand cylinder Ell through port I33, tube W8, and port ll. At the same time port it or the tube I95 connected therewith will be closed through the relief valve R. At this time the chamber 6 below the piston of the right hand cylinder 89 will have the oil drawn therefrom through port 7%, tube Hi9, port I34, port Iill, and tube Hill to the pump PI which oil will be forced by the pump through tube m2 to the reserve tank T and through tube we to valve V. This chamber e will also be relieved through the relief valve R and connections before described.

It will be seen from the foregoing description that oil is admitted under pressure to the chambers e and relieved therefrom alternately and that the reversing valve V and relief valve R are accurately operated through movement of the air compressing pistons. Upon upward movement of either of the pistons P air is compressed within chamber 0, which compressed air is forced through yalve 28 and a tube 225 into the supply tank S.

Simultaneously with the upward or compressing movement of either of the pistons P the other piston with its cylinder 50 is moving downwardly and atmospheric air will be admitted to its chamber 0 through one of the intake valves 22. The downward movement of either piston also effects downward movement of piston 10 through the rod it resulting in 'air being compressed in chamber at which compressed air is exhausted through valve 38 and is conducted through tube 226 or 22! to chamber 0 above the downwardly moving piston through the other intake valve 22, air being admitted to chamber 11 through the intake valve 48 upon upward movement of piston P.

It will thus be seen that a double action compressing means is provided and that upon upward movement of either piston P through oil pressure within chamber 6 a relatively large volume of air is compressed in chamber 0 and delivered to the storage tank S and that this upward movement of piston P through the walking beams 88 imparts downward movement to the other piston P which through its rigid connection with its associated piston 10 causes air to be compressed within chamber 01 which is delivered into chamber 0 above the downwardly moving piston under a pressure of approximately 50 lbs. whereby upon upward movement of this same piston this air together with a volume of atmospheric air which was admitted through valve 22 to chamber 0 upon the initial downward movement of the piston will be compressed to a very high pressure when this piston again moves upward through fluid pressure in chamber c.

It will thus be seen that relatively large volumes of air are capable of being compressed to a relatively high pressure by the utilization of a relatively small volume of oil admitted to chamber e under operating pressure through the pump PI in turn operated by a relatively small motor M.

While in the foregoing an operative construction has been set forth and while many secondary parts which obviously would be incorporated in actual construction have not been included it is to be understood that in all joints or connections suitable gaskets where not heretofore mentioned are utilized.

It is to be further observed that some means should be provided for proper lubrication of the pistons particularly those which are remote from any possible contact with the oil for operating the pistons P. A satisfactory means of lubrication may be provided by the introduction of small quantities of oil to the Valves communicating with the cylinders in which the respective pistons are disposed and which oil may be placed on the spring or other moving parts of the valve at certain intervals or the valve casing may be provided with a suitable oil cup in which may be maintained a supply of oil which will constantly flow to the valve.

It may also be found desirable to eliminate noises which may develop in the operation of the valves and accordingly the valve seats may be of a composition which will positively silence the valve during the operation thereof.

Referring again to the reversing valve, should wear between plunger M4 and the wall of opening I24 develop to an extent as to permit leakage of oil past the plunger I44 it may be found desirable to provide same with rings in the nature of the piston rings heretofore referred to which will positively preclude the escape of oil past the plunger.

In Figs. 14 and 15 is illustrated a modification of my invention and in which a plurality of relatively small compressing cylinders 23B are utilized in cooperation with those already described.

As illustrated there are eight cylinders 23!] four of which are operated in alternation with the other four and which operation is preferably effected by substituting for the ring members 82 rectangular plates 23l to each of whose corners is secured a piston rod 232 extending upwardly through support I I and into an aligned cylinder 230. Each of the piston rods 232 is provided with a piston 233 which may be similar to piston p or of the skirt form later to be described. Each of the cylinders 230 is provided with an intake valve 234 and an exhaust valve 235 which exhaust valves are adapted for connection with suitable tubes which may lead to the supply tank S or those common to one cylinder It] may be in connection with chamber 0 of the other cylinder ll] thereby providing air initially at a much higher pressure preliminary to the compressing movement of the major piston P. If desired intake and exhaust valves may be provided at the other end of each of the cylinders 230 whereby pistons 233 will be double acting.

The piston-s 233 will move concurrently with pistons P due to their connection with plates 23! and by the provision of the additional air compressing cylinders a much greater volume of air can be compressed by the same fluid pressure supplied by the pump Pl.

Upon inspection of Fig. 14 it will be readily seen that eight additional cylinders may readily be provided and supported on base member 44, the rods of whose pistons being secured to plates 23| or for simplicity of construction may be provided by extensions of the rods 232.

In Fig. 16 I have illustrated another form of cylinder which is of toggle type and which while it is not in itself novel is well adapted for connection with the operating means such as ring members 82 or plates 23! and which may be associated with the construction disclosed in Fig. 1 or Fig. 14 whereby a still greater quantity of air may be compressed.

In Fig. 17 I have illustrated a modified form of piston indicated at 240 which is of the skirt type and is provided with a pair of piston rings 24! and which may be substituted for any of the before mentioned pistons.

Having disclosed one specific embodiment of my invention it is to be understood that I am not limited thereto but am at liberty to resort to such modifications or substitutions as fairly come within the scope of the subjoined claims.

What I claim is:

1. In an air compressing mechanism, in combination, a cylinder, a piston in said cylinder, inlet and exhaust air valves communicating with said cylinder on one side of said piston, inlet and.

.outlet piston operating fiuid ports in said cylinder on the opposite side of said piston, a second cylinder, a piston in said second cylinder, a rigid connection between said pistons, a third cylinder supporting said first piston and movable therewith, a guide plate supported by said third cylinder for movable engagement with said second cylinder, a plurality of additional cylinders each having a piston movably disposed therein, and connections between said guide plate and said last pistons for operating same upon movement of the piston supporting cylinder.

2. A structure as defined in claim 1 wherein said guide plate is rectangular, and wherein said additional cylinders are vertically disposed above said guide plate and with said connections axially disposed within said additional cylinders and secured to said guide plate adjacent the corners thereof.

3. In an air compressor, in combination, a pair of compressing units, each of said units comprising a cylinder, a second cylinder coaxially disposed with relation to said first cylinder, a third cylinder movably disposed in telescopic relation with respect to said second cylinder, a piston supported by said third cylinder and cooperating with said first cylinder for compressing air therein upon movement of the piston in one direction, a second piston rigidly supported by said first piston and cooperating with said second cylinder for compressing air therein upon movement of said first piston in the opposite direction, an operative connection between said pair of compressing units for synchronous movement of said pistons, and power supply means for moving the pistons.

4. In an air compressor, in combination, a cylinder, a piston movably disposed in said cylinder, a second cylinder coaxial with said first cylinder, a piston movably disposed in said second cylinder, an adjustable connection between said pistons, a pair of inlet valves and an exhaust valve cooperating with said first cylinder, an intake and an exhaust valve cooperating with said second cylinder, a conduit connecting one of said intake valves cooperating with said first cylinder with said exhaust valve cooperating with said second cylinder whereby upon movement of said first piston in one direction atmospheric air is admitted through one of said intake valves to said first cylinder while air is being compressed by said second piston in said second cylinder and forced through said exhaust valve cooperating therewith, conduit, and the other intake valve cooperating with said first cylinder for further compression together with the air admitted through the first named intake valve cooperating with said first cylinder upon movement of said first piston in the opposite direction.

5. In an air compressor, in combination, a master cylinder, a master piston in said cylinder, 21. secondary cylinder, a piston in said secondary cylinder operatively connected to said master piston, valve means for admitting atmospheric air to each of said cylinders and exhausting compressed air therefrom, a third cylinder supporting said master piston mounted for reciprocatory movement between said first two cylinders, valve means for controlling piston operating fluid pressure between said master cylinder and said movable cylinder, and a connection between said master cylinder and said secondary cylinder for admitting air compressed in said secondary cylinder to said master cylinder for further compression therein.

6. In an air compressor, in combination, a pair of master cylinders, a reciprocating piston in each of said cylinders, a secondary cylinder projecting within each of said master cylinders, a reciprocating piston in each of said last cylinders connected for unitary movement with said first piston, valve means for admitting atmospheric air to each of said cylindersand exhausting compressed air therefrom, means for admitting piston operating fluid to said master cylindersin succession and .means for exhaustingthe fluid.

therefrom whereby said master pistons are reciprocated in alternation forcompressing .air in said master cylinders, connections between said master cylinders and said secondary cylinders for admitting air compressed in said secondary cylinders to said master cylinders for further compression therein. I

'7. The construction defined in claim 6 wherein said means for admitting and exhausting the piston operating fluid comprise valves, and means operable through movement of said master pistons for actuating said valves.

8. In an air compressor, in combination, a pair of fixed cylinders, a second pair of fixed cylinders, each of said second cylinders coaxially disposed with relation to one of said first cylinders, a cylindermounted for reciprocationbetween each of said first cylinders and one of said second cylinders, a piston fixed to each of said reciprocable cylinders for movement within. one of said first cylinders, a piston supported by each or" said first pistons for movement within one of said second pair of cylinders, a pair of inlet valves and an exhaust valve cooperating with each of said first cylinders on one side of the piston therein, an inlet and anexhaust valve cooperating with each of said second cylinders on one side of the piston therein, a tube connecting the exhaust valve of each of said second cylinders with one of the intake valves of each of said first cylinders, an inlet and an outlet port communicating with each of said first cylinders on the opposite side of the piston therein, and means for controlling the flow of piston operating fiuid through said ports for actuating said pistons.

9. The construction defined in claim 8 in which said reciprocable cylinders are interconnected by a walking beam, and connections between said walking beam and said means for automatically operating same.

10. The construction defined in claim 8 in which said controlling means comprises a reversing valve for admitting piston operating fluid to said first cylinders alternately and a relief valve for relieving the fluid pressure in said first cylinders alternately with the admission thereto.

11. The construction defined in claim 8 in which the exhaust valve of each of said first cylinders is connected by a tube with a storage tank and in which a fluid reserve tank is in communication with said controlling means.

12. In an air compressing mechanism, in combination, a pair of cylinders, a piston in each of said cylinders, an inlet and an exhaust air valve communicating with each of said cylinders on one side of'the respective piston, inlet and exhaust piston operating fluid ports in said cylinders, on the opposite sides of said pistons, a reversing valve for controlling the flow of fluid into said inlet ports, a relief valve for controlling the fiow of fluid through said exhaust ports, operative connections between said pistons and said valves for operating the valves through movement of the pistons, an air storage tank connected with said exhaust valves, and a reserve tank associated with said relief valve.

13. In an air compressor, in combination, a pair of cylinders, a piston movably disposed in each of said cylinders, an inlet and an exhaust air valve communicating with each of said cylinders on one side of the piston therein, an inlet and an exhaust piston operating fluid port in each of said cylinders on the opposite side of the piston therein, a fluid pump, a reversing valve in communication with said inlet ports and said pump, a relief valve in communication with said exhaust ports and said pump, a fluid reserve tank in communication with said relief valve and said pump, operative connections between said pistons and said valves for operating the valves through movement of the pistons, and a compressed air storage tank in communication with said exhaust valves.

14. The construction defined in claim 13 in which said reversing valve comprises a casing, a fluid pressure chamber in said casing, a reciprocable plunger in said casing, a slide valve operable by said piston for successively admitting fluid from said chamber to opposite ends of said plunger for hydraulically reciprocating same, a slide valve for successively admitting fluid from said chamber to said inlet ports, and a connection between said plunger and said last slide valve whereby same is operated upon movement of said plunger. I

15.-The construction defined in claim 13 in which said relief valve comprises a casing, three ports in said casing two of which are adapted for communication with said exhaust ports and the other of which is adapted for communication with said reserve tank and pump, and a rotary valve member disposed in said casing and provided with an angular port for successively placing said last port into communication with one and then the other of said two ports.

16. In an air compressor, in combination, a pair of concentrically disposed fixed cylinders, a third cylinder mounted for reciprocation between said concentrically disposed cylinders, a piston supported by one end of said last cylinder for reciprocation in one of said first cylinders for compressing air therein upon movement of said third cylinder in one direction, a rod having one end thereof fixed to said piston, a second piston secured to the other end of said rod and disposed within the other of said first cylinders for reciprocation therein for compressing air upon movement of said third cylinder in the opposite direction, valve means for admitting atmospheric air to and discharging compressed air from each of said first cylinders, and means for imparting reciprocatory movement to said third cylinder.

17. In an air compressor, in combination, a pair of cylinders, a fiuid operated piston in each of said cylinders, a valve for controlling the admission of operating fluid to said cylinders, a separate valve for controlling the discharge of operating fiuid from said cylinders, a walking beam pivotally supported between said cylinders and having the opposite ends thereof connected with said pistons, and an adjustable connection between the walking beam on opposite sides of the pivotal connection thereof and each of said valves for operating same in timed relation to the movement of said pistons.

18. In an air compressor, in combination, a cylinder, a piston reciprocably mounted in said cylinder, an inlet and an exhaust air valve connected with said cylinder on one side of said piston, a pair of ports communicating with said cylinder on the opposite side of said piston, a valve forintermittently admittingpiston operating fluid to said cylinder through one of said ports for operating said piston, a valve for relieving piston operating fluid from said cylinder through the other of said ports in alternation with the admission thereof, connections between said piston and said valves for actuating the valve through movement of the piston, a second cylinder, a piston therein, an inlet and an exhaust air valve connected with said second cylinder, a rigid connection between said pistons for movement of said second piston concurrently with said first piston, and a connection between the air inlet valve of the first cylinder and air exhaust valve of the second cylinder for admitting air compressed in the second cylinder to the first cylinder for further compression therein.

19. In an air compressor, in combination, a cylinder, a piston movably disposed therein, a second cylinder, a piston movably disposed in said second cylinder and connected with said first piston for operative or compressing movement during the idle or non-compressing movement of said first piston, guide means connected with said first piston and movably engaging said second cylinder, and a plurality of additional cylinders each provided with a piston operatively connected with said guide means.

20. In an air compressor, in combination, a pair of cylinders, a piston reciprocably disposed in each of said cylinders, a rectangular plate rigidly supported by each of said pistons, a connection between said rectangular plates for causing uniform movement of said pistons in opposite directions, a plurality of additional cylinders associated with each of said first cylinders, a piston reciprocably disposed in each of said last cylinders, and a rigid connection between each of said rectangular plates and the pistons in the respective cylinders associated with each of said first cylinders.

21. In an air compressor, in combination, a supporting member, a cylinder secured at one end thereof to said supporting member, a base disposed below said supporting member, a second cylinder of less diameter than said first cylinder and having one end thereof secured to said base with the opposite end projecting within said first cylinder in concentricv relation thereto, a third cylinder concentric with said first and second cylinders and supported for vertical movement therebetween, a piston supported by said third cylinder and movable within said first cylinder for compressing air therein, a second piston supported by said first piston and movable within said second cylinder for compressing air therein, and means for imparting vertical movement to said third cylinder.

22. The construction defined in claim 21 together with a guide plate supported by said third cylinder for movable engagement with said second cylinder.

EDWARD J. JODRY. 

